Watermelon field weed types, causing harm to the weeds are mainly cattle grass, barnyard grass, dogwood, barnyard grass, paintbrush and other grass weeds, in addition to some broadleaf plant weeds such as bird's tongue tea grass, cattle flour wisps, honey spikes Ma Matsunzi, horse tooth water pipe, etc.. This kind of weed generally has two peak periods of emergence, the first peak time is accompanied by the excavation of watermelon melon seedlings, accounting for 60% of the number of weed emergence of watermelon full-life cycle; the second peak time in the watermelon vine length of 70 centimeters or less.

Watermelon field with herbicide weed control is a provision of a more rigorous technical, the application of appropriate to get rid of weeds, so that all normal growth and development of watermelon. But in recent years, I found in the research, melon farmers due to unscientific use of herbicides, not both the watermelon field before and after doing the spraying and crop reasonable layout of the situation, even if the candidate then correct herbicides, but the same or the occurrence of the drug damage to the production and processing of the damage caused by the should not have.

The following herbicides are more sensitive to watermelon, the application of caution:

1, dichloroquinolinic acid

Rice fields in the conversion of watermelon, be sure to research what herbicides have been used in the rice field previous crop. Nowadays, rice fields with dichloroquinolinic acid hoeing is increasing, the herbicide's residual time is long, there is no economic development at this stage of the reasonable way to make the residual dichloroquinolinic acid in the soil quickly dissolved, planted after the stubble crop of watermelon, watermelon will cause drug damage. Not only that, some of the herbicides sold on the market at this stage, such as "QiuHuan 1 +1", only need to find out what it is composed of, it is known that the rice paddy field before the application of this type of herbicides, planting watermelon after the crop should be changed to other high safety factor of the herbicides.

The above "Autumn Happiness 1+1", the composition of dichloroquinaldic acid and cyhalofop-butyl, the latter one in the rice field after the use of the residual period is very short, there is no residual damage to the crop, while the first one in the soil environment for a long time, it is very easy to a wide variety of stubble, such as watermelon, cantaloupe, squash, cucurbits, beans and other melon vegetables comparative. The more sensitive crops such as watermelon, cantaloupe, gourd, bean curd and other melon vegetables lead to harm, last year, even if the amount of dichloroquinolinic acid used in accordance with the conventional use of the field, the next year can not be planted in watermelon crops, to prevent causing drug damage.

2, hay must be net (20% thifensulfuron-ethyl herbicide)

Thiophenesulfuron is selective systemic delivery type sulfonylurea herbicide, the sale of hay must be sold on the market for 20% thifensulfuron -ethyl herbicide wettable powder containing thifensulfuron 1%, ethanol 19%, thifensulfuron is used to hoeing wheat with good results, the drug can be quickly dissolved by the organisms, in the soil environment, the drug half-life under the sunlight. The drug half-life in the soil environment to 6-12 days under the sun, no light for 14 days under the sun, at a temperature of 30 ℃, pH value of 8 in the soil drug half-life of 12 hours, generally feel that the solution can be planted in 30 days after the stubble crop.

But the ethalfluralin contained in it can be digested and absorbed by green plant seedlings, monocotyledonous plants according to the bud sheath digestion and absorption, dicotyledonous plants from the hypocotyl digestion and absorption, so that seedlings, young roots to terminate the growth and development. Watermelon and other broad-leaved plant crops are sensitive to thifensulfuron and other sulfonylureas such as glycemic herbicides, even if there is only a small amount of this herbicide residue in the soil layer, it is possible to jeopardize the growth and development of the watermelon seedling, should be used with caution, but wherever the use of hay bi-purification herbicides in the field, it is best not to have to plant a short period of time to plant watermelon and other broad-leaved plant crops.

3, nicosulfuron

Nicosulfuron is a sulfonylurea herbicide, in the soil environment, the residual period is long, on a variety of stubble crops may cause residual damage, in which contains watermelon. According to the relevant materials in detail, the previous crop application of fumisulfuron-methyl pure drug mu use 4 grams above, planting watermelon and other crops need to be spaced 18 months, otherwise it will cause more serious damage to the watermelon, its clinical symptoms for the leaf green loss of green, the growth and development of the inhibition of the more serious main performance of the main stem of the lack of water wilting, withering.

4, ethofumesate

Watermelon and other melon vegetable crops are more sensitive to ethofumesate. Ethoprop is a pre-emergence herbicide, drugs are digested and absorbed by the green plant, the green plant body affects the nucleotide metabolism and protein synthesis, so that seedlings, young roots to terminate the growth and development, and thus generally feel that ethoprop must be in the weed born before the application of the excavation of the main stem of the excavation of the effectiveness of the main stem of the weaker.

But this does not mean that watermelon planted after the application of ethofumesate is not easy to watermelon harm. In fact, watermelon, melon, cantaloupe, winter melon, etc. are very sensitive to ethofumes, this crop field can not apply ethofumes, there are experiments to illustrate that the watermelon in the stretching period of the spraying of ethofumes, a week later observation, melon vine slim, no birth point at the top of the vine, light green leaves, the new transmission of the leaves wrinkled, small and rolled.

At this stage, a lot of examples have been found in the watermelon field around the application of ethofumesate due to the occurrence of altered drug damage. The watermelon is subjected to the situation that the newborn body suffers from the control due to the ethalfluralin-altering drug damage. Especially in the fruiting period of the watermelon field, if suffered ethchlorothiazide change of drug damage, the damage will be more serious, specific performance for watermelon shoot tip leaf blight, generally in the medicine after 20 hours will occur drug disease. It has been observed that the medicine drops SF Express change leads to the spacing of the infestation can reach 80-100 meters.

5, Jinduer (96% fine isopropyl metolachlor)

Jinduer (96% fine isopropyl metolachlor), generally available to organic chemical weed control in watermelon fields, but used at too high a temperature, the drug is dynamic, a small amount of the drug can be a good hoeing effect. However, the use of a slightly larger amount of watermelon is very easy to lead to drug damage, should be noted.

The reason why watermelon is affected by Jinduer drug damage may be the spraying of drugs after the occurrence of ultra-low temperature rainy and precipitous sunny rainy weather, the arch natural ventilation is not immediate, evaporation out of the drug on the watermelon caused by the drug damage. Its clinical symptoms are reflected in the watermelon seedlings leaves turn yellow, crooked, the main stem does not grow, some wilting, not wilting the main stem does not sit on the melon or knot melon small.

Therefore, watermelon planted under mulch cover should be sprayed 1-2 days before covering the film. With a small plastic greenhouse cover planting watermelon, the application of jinduer and its seconal, florine, dimethyl pentylenetetrazol and other available herbicides, easy to cause "flow back to the drug", that is, in the arch greenhouse temperature is high, sprayed in the soil layer of the surface layer of the drug is easy to volatilize, and then integrated into the greenhouse membrane established in the droplets of water containing herbicides droplets to the watermelon seedlings, will cause shoots shriveled or in the melon seedling. cause the bud eyes to shrivel or produce medicine spots on the melon leaves. Application of non-drip agricultural film, arch greenhouse environment when high humidity immediately unlock the plastic greenhouse on both sides of the natural ventilation, the volatile drugs immediately dispersed, can prevent the watermelon caused by drug damage.